Question

A box contains 3 plains pencils and 7 pens . A second box contains 6 color pencils and 2 crayons one item from each box is chosen at random. What is the probability that a pen from the first box and crayon from the second box are selected

Answer 1

Well to solve these type of question it is very easy to make a tree diagram and then solve them. How ever i have done it here for you.

So basically we have to get a pen from the first box so its probability is 7 / 10.

Similarly, we have to get a crayon from the second box so its probability is 2 / 8.

Now by counting principle we can multiply the two probabilities so 7/10 * 1/4 which becomes equal to 7/40.